We are going through this EXACT scenario (without the montessori reccomendations though) with DS (1st grader) this year! I could be you! Wow!
Anyway, just wanted to ask, has anybody mentioned to you that an IQ of 130 is "gifted" or "very superior", it is the top 2 percent of the population. 130 is the number needed to qualify for full time gifted services here in our school district. I would assume it is the same elsewhere but I don't know. Is there possibly a full time or part time gifted program at a nearby school that might work? How about a school that uses gifted inclusion? The gifted programs do lots more "hands on" stuff and lots of "why does this work" stuff, instead of worksheets and textbooks. There's alot more homework but the kids are much more excited about school and seem to enjoy the work.
Anyway, our DS has been diagnosed by his teacher (who also does not have an MD after her name) as "ADHD". Well, guess what, He's not! We also took him and had him tested for behavior, IQ, LD, memory, etc. Turns out he's really, really smart and in the "superior" range with an IQ of 120 or so and has no signs of LD's or anything else. He doesn't qualify for gifted but he is smart. He does have a few characteristics of an ADHD kid (fidgety, makes noises, trouble completing his work) but definitely does not qualify as ADHD or anything else. He is a NORMAL 6 year old boy! Even after we had the testing done (at great expense) the teacher refused to drop the matter and we had to go before a student study team supposedly to "help" my son. I believe the "help" they want is for him to take drugs and "sit down and shut up" not actually learn to control his behavior, just stop being a problem for them.
Anyway, we absolutely LOVE our school and have a daughter in 4th grade at the school as well. We actually were quite pleased with this teacher when DD had her but are pretty unhappy with her theories on DS. So, this is an ongoing situation for us but we're hopeful it will all work out.
Keep us posted on your situation, I'm very curious as to how it turns out.